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Installing A FAST™ XFI™ System In A 1964 Fuel Injected HEMI Dodge

Rich Nedbal’s first Mopar was a 1964 Dodge 2-door hardtop that he bought in 1963 after graduating from high school. It had a 305 HP 2 barrel 383. Sooner or later we all want to rebuild that special first car. So in 2000 he went looking for a 1964 Dodge carcass. He found a very straight car in Washington State that had been parked for 27 years. It had a 318 poly motor, pushbutton 727 and even though it looked rough, it was intact, had manageable rust, all its chrome, cost only $2000, and it was running.

If he was going to build a car capable of handling a yet-to-be-defined Hemi, it had to be be mechanically stout. So he kept the body and transmission but that’s about all. He stiffened the chassis with 2″ x 3″ full-length frame connectors welded into the floor pan. Then he welded in mini tubs and installed a Ford 9″ housing and a 35 spline Mark Williams locker with 3.20 gears and disc brakes. Ladder bars kept everything in place. Lastly, coilovers went in, punching into the trunk.

In front, Rich installed disc brakes, power rack-and-pinion and a tubular K-member. He used the largest Wilwood disc brakes that fit inside the 17″ wheels and a large bore master cylinder. The 727 was rebuilt and beefed up by TCI, a kick down kit was added and a 2500 stall converter installed.

The project was put on hold when Richard founded and then spent several years building his business, FAST Man EFI. He built many street and race Hemis during this time. After selling fuel injection systems to people all over the world, Richard knew his Hemi had to be EFI. He also knew that he wanted a large displacement Hemi because those 572 street Hemis that he built for his customers were well liked.

Just when he started working on the car again, Richard was asked to write a book about building second generation, 426 style Hemis. Researching and writing his book, How to Build Max-Performance Hemi Engines, turned out to be the perfect way to build the state-of-the-art, street EFI Hemi he was looking for. It had to use a solid roller cam, utilize the best fuel injection system and run on pump gas. Knowing cam specs and compression ratio are major factors in streetability, Richard kept the compression ratio to 10:1 using Stage-V aluminum heads. But the cam was different from what most Hemi guys would use. It was short on duration for the displacement and had a wide lobe separation. That gave the engine a nice wide, flat torque curve in the RPM range where it would actually be driven. It also idled at 800 RPM, had 14″ of vacuum and tapped into that torque immediately off idle. The throttle response was impressive and with that much displacement and dual 3″ exhaust, it had a sound that was definitely all Hemi.

Really differentiating his Hemi from a crate motor meant doing something visible. Putting dual throttle bodies on a Stage-V manifold was a good start. Very few people were used to seeing coil-on-plug ignition systems on a second generation 426 style Hemi. So Richard decided to ditch the distributor and run eight coils. Blocking off the distributor and showing how to get a system like this to work was going to be paramount to differentiating FAST Man EFI from other companies.

Richard knew that putting port injected EFI on a 426 style Hemi would be difficult, but he discovered a Stage-V bolt-on dual throttle body EFI manifold. Two FAST™ polished throttle bodies (#307603P) on the manifold made the induction side of the EFI Hemi project simple. Although each throttle body included a TPS and an IAC, only one of each was used. For ignition Richard could have installed a FAST™ dual-sync distributor (#305013), but he wanted it truly distributorless. Richard decided to use an MSD cam sync sensor and embed a magnet in the cam gear. This was very easy to fabricate since the cam gear was exposed on Richard’s Hemi. That took care of the cam signal. Then Richard simply used a crank trigger wheel for the crank signal.

Richard chose MSD multiple spark coils that pack a lot of energy and were made for the GM LS1. The FAST™ XFI™ with the XIM™ ignition controller and a FAST™ LS1 harness (#301311) made it look easy. But the LS1 firing order was different from his Hemi. Richard had to swap some wires to change to the Hemi firing order and to switch the cam and crank inputs to be compatible with the inductive crank and cam pickups.

The Hemi definitely looked different with the coils mounted on top of the valve covers. The engine fired right up on the Mopar Engines West dyno. Richard adjusted the crankshaft reference angle in the software until the ECU ignition timing and the actual engine timing matched. Then he adjusted the air/fuel ratios at various points in the fuel map. This was done prior to the XFI 2.0™ release. With the 2.0 version Richard would have let the system learn and tune itself, and then he could fine tune any area he wanted.

Once assembled, Richard made a few short pulls, data logging various parameters. This critical data log was the guide to adjusting the A/F ratio at higher RPM points. Once the A/F ratio was in the ballpark, Richard switched the ECU into closed loop, meaning that the ECU made its own adjustments using the target A/F map as the guide. He then made a few short pulls and used the data log results to change various fuel cells to minimize the amount of ECU correction. If you can get the ECU closed loop correction under five percent, you’re good to go. Richard targeted 12.8 for the max power A/F ratio and the fourth pull resulted in this setup.

Richard wanted a Hemi that would start and run like a Lexus but still have the torque to shred the tires at will. He reached that goal. On 91 octane pump gas it sounded docile and fairly quiet, until he pushed on the pedal. With its 315/35ZR17 rear tires, the car would break the tires loose in any gear. Highway entrance ramps required his full attention, even if he was already going 40 MPH.

The FAST™ XFI™ system, combined with the camshaft Richard designed and a special high MPG cruise tune, allowed him to achieve reasonable fuel mileage considering the Dodge’s 725+ HP potential. The high MPG tune did a few things that EFI excels at. Under low load flat cruise conditions the engine ran very lean, the timing advanced (just like the old vacuum advance days), and the system turned off the injectors entirely during any deceleration. Pump shot was also restrained as long as the rate of gas pedal depression was low. On a recent 138 mile trip, the car made 13.9 miles per gallon, which Richard feels is pretty good for such a stout engine in a heavy car.